1. Field of the Invention
The present invention relates to an improvement in a camera using a film with a magnetic memory portion, and comprising a film transporting means for transporting a film and a magnetic head for writing or reading information to or from the magnetic memory portion of the film (sometimes referred to herein as "magnetic memory portion") while the film transporting means is transporting the film.
2. Description of the Related Art
A camera using a film with a magnetic memory portion has been disclosed in U.S. Pat. No. 4,864,332. The camera disclosed therein is arranged to write photographic information pertaining to a shutter time, an aperture value, a date, a title, etc., to the magnetic memory portion, and to read out the written information by means of a magnetic head.
In a camera of the aforementioned type, when the information is read from the magnetic memory portion of the film by the magnetic head, there is a proportional relationship between a transporting speed of the film and a magnitude of a signal read from the magnetic portion, i.e., a magnitude of a change in magnetic flux. Therefore, in order to stably read the signal from the magnetic memory portion, the transporting speed of the film must be as fast as possible.
However, the fast transporting speed of the film prevents a large amount of information from being written to the magnetic memory portion of the film for the following reason.
When the information is written to the magnetic memory portion of the film by the magnetic head, a fixed time T is required for the electric current applied to the coil portion of the magnetic head to reach a steady state. In order to write a large amount of information to the magnetic memory portion, it is necessary to make the writing frequency high. However, when the transporting speed of the film is fast, the time T occupies a large fraction of one signal since the time T is fixed, and therefore a large amount of information cannot be written stably to the magnetic memory portion.